Transparent Material in Blender but not in Unity
When working with transparent textures you'll have to set up a separate material in Unity that has it's surface type set to transparent and another material for rendering the opaque parts, In blender you'll have to assign an extra material slot for this transparency the extra slot will show up in the material options for your model in Unity.

Select the parts of the mesh you want to use the transparency and click "assign"

In Blender



In Unity